The two major research directions for the Division of Hematology at Stanford are malignant hematology and vascular biology. This involves both basic and clinical research. The program described herein will train postdoctoral fellows for a career in academic hematology. Candidates with MD or MD/PhD degrees who have completed training in Internal Medicine will be admitted to the three-year program. The first year of the program consists of an intensive training in clinical hematology, including benign and malignant hematology, stem cell and bone marrow transplantation, and transfusion medicine. In Year 2 and Year 3, the trainees will devote the majority o their time to research-based study. This will be done in a Basic-Scientist Pathway or a Clinical Investigator Pathway. The Basic-Scientist Pathway is primarily for trainees with substantial prior basic research experience, focusing on malignant hematology, vascular biology, and related basic research areas. The Clinical Investigator Pathway provides formal training in clinical research and incorporates the K30 clinical Investigator Training program at Stanford under the direction of Dr. Julie Parsonnet, leading to a Master's degree at the completion of formal training. In addition to the didactic training, the Clinical Investigator Pathway fellow will also conduct hands-on clinical trials in the Division of Hematology. Fellow stipend support for the research training in Year 2 and Year 3 is requested in this grant application. More than three years of training is often required. Trainees are encouraged to apply for and obtain their own independent mentored research training support in Year 4. For each fellow, the research training will be supervised by a full-time faculty member in the Division of Hematology, or one of a number of associate faculty members at Stanford University, representing disciplines relevant to hematology training. These include faculty in biochemistry, molecular pharmacology, microbiology, immunology, pathology, medical oncology, bone marrow transplantation, cardiology, pediatrics, epidemiology, outcome research, and health policy. A mentoring committee will meet regularly with each fellow, and the progress of each fellow will be reviewed by the Program Director and the Training Program Steering Committee. At the conclusion of their training, trainees will be prepared for a career in academic hematology, as an independent investigator at the forefront of science and hematology. (End of Abstract)